For an optical glass having a high refractive index and low-dispersion properties, a so-called fluorophosphate-based glass containing phosphorus and fluorine has been known (e.g. refer to Patent Documents 1 to 7, English family members of Patent Document 5, US 2008/132400A1 and U.S. Pat. No. 7,989,377, English family members of Patent Document 6, US2009/298668A1, U.S. Pat. No. 8,198,202, US 2012/245015A1 and U.S. Pat. No. 8,431,499, the entire contents of which are incorporated herein).
(Patent Document 1) Japanese Patent Laid-Open Publication No. 2010-235429
(Patent Document 2) Japanese Patent Laid-Open Publication No. 2011-37637
(Patent Document 3) Japanese Patent Laid-Open Publication No. 2012-12282
(Patent Document 4) Japanese Patent Laid-Open Publication No. 2012-126603
(Patent Document 5) Japanese Patent Laid-Open Publication No. 2008-137877
(Patent Document 6) Japanese Patent Laid-Open Publication No. 2009-286670
(Patent Document 7) Japanese Patent Laid-Open Publication No. 2003-160356